help determining child process status

[Guy Harris]

 >If you know the pids of the sub-tasks, you can do a kill(pid, 0). Under
 >Xenix, kill(pid, 0) returns 0 (zero) if the task is still running or 
 >-1 if the task is terminated. I have tried this under Xenix and it works.
 >However, I know that it is not very portable to other flavors of Unix.

Uhh, it works under 4.[23]BSD and systems derived therefrom, and System
V Release N for values of N greater than some M (M is at least 2, as I
remember) and systems derived therefrom, so it's more portable than you
might think.